A construction toy product incorporating principles of the above mentioned United States patents and widely marketed under the trademark "K'NEX", is comprised of a plurality of molded plastic connectors which can be assembled with molded plastic rod elements of graduated lengths to form complex, coherent skeletal structures. The connector elements are of special design, comprising one or more pairs of cantilever-mounted gripping arms oriented along radial axes extending from a defined common point of the connector. Opposed pairs of the gripping arms form sockets for the lateral, snap-fit reception of end portions of the rod elements. Outer portions of the gripping arms are formed with axially extending grooves arranged to grip cylindrical portions of the rod elements. Each pair of the gripping arms is also provided with opposed, transversely disposed ribs, and these ribs cooperate with annular grooves formed in the rod elements, closely adjacent their ends.
When a rod element is laterally snap-fit assembled with a connector, the grooved outer portions of a pair of gripping arms engage and grip the cylindrical end portion of the rod element and hold it in alignment with the axis of the socket. The opposed ribs of the gripping arms are received within the annular groove adjacent the rod end and serve to prevent axial movement of the rod. The ability of the rod elements to be assembled with the connectors by lateral snap-fit motion permits the assembly of rod elements with an opposed pair of connectors at each end, without requiring the connectors to be separated to accommodate the assembly, and thus accommodates the assembly of large and complex skeletal structures.
The present invention is directed to a novel and advantageous design and construction of panel elements which are adapted to be incorporated into a skeletal structure of the type described above in a manner to allow enclosure or partial enclosure of skeletal structures and at the same time forming an integral part of and thus enhancing such structures. To this end, panel elements according to the invention are formed of an injection molded structural plastic material and include a thin, flat central area bounded by side edges. The panels may take a variety of polygonal shapes, most typically in the form of a square or a right isosceles triangle. Adjacent panel side edges define corner regions of the panels, and at each such corner region there is formed an integrally molded rod tip element which projects outward from the corner region and has an axis aligned substantially in the plane of the panel. Each of these rod tip elements has a configuration corresponding to the end configuration of the before described rod elements, being thus adapted for lateral snap-fit assembly between an opposed pair of gripping arms of a connector element. Preferably, at least certain of the integral rod tip elements are arranged in aligned pairs, spaced apart a predetermined distance corresponding to the length of a rod element of the construction toy set. In this respect, in the described construction toy set, rod elements are provided in a predetermined graduated series of lengths and for each size and shape of panel according to the invention, at least opposed integral rod tip elements of at least one pair thereof are spaced apart according to the length of a rod of the graduated series thereof.
In one preferred form of the invention, panel elements are of square configuration, formed with opposed pairs of integral rod tip elements aligned with diagonals of the square. In another advantageous form of the invention, the panel may be of triangular configuration and opposed pair of rod ends are aligned along one side edge of the panel, forming the base of a right isosceles triangle. A third integral rod tip element is formed at the apex of the triangle, bisecting the angle of the apex.
To advantage, the side edges of the panel elements are generally straight. Each corner region of the panel is defined by a corner edge having concave arcuate contours joining adjacent side edge portions, and the integral rod tip elements project outward from the concavely contoured corner areas. In a particularly preferred form, the outer ends of the rod tip elements are confined substantially to an area defined by said concave edge contours and by intersecting extensions of adjacent side edges of the panel.
The panel elements of the invention can be readily incorporated in and/or removed from existing complex skeletal structures without the necessity of distorting the structure. When assembled, the panels are an integral part of the structure and can be utilized both in conjunction with and, in some cases, in place of the usual rod elements.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of preferred embodiments and to the accompanying drawings.